The present invention relates to an identification coding for print ribbons and other ribbons or webs that have individual segments or panels that are different from other segments and must be positively identified for desired operations in a printer or other apparatus. In particular the coding is used between groups of colors on a color printing ribbon and also between individual frames of different colors, which gives individual controls for a wide variety of functions.
The thermal print ribbons that are presently used in thermal printers are divided into different color dye carrying frames, panels, blocks or segments. Thermal printers require a sensing system, which is capable of identifying the location of the individual colored panel or frames of the web or ribbon used, as well as the start of each group or sequence of the color dye panels or frames.
The ribbon is held against a platen that is rotatable, and the ribbon moves with the platen during printing, when a thermal printing head engages the ribbon and causes transfer of a colored dye onto a card or substrate positioned between the ribbon and the platen, and which is also moving with the platen. The printing sequence is carried out under a central control that receives signals indicating the presence of a card or other substrate on which the information is to be printed, and also receiving signals indicating what color frame of the ribbon is in position under the print head and for lining up or registering the card and ribbon.
In the past, index marks had been used along the side edges of the ribbon for indicating when the sequence of different color frames starts and is repeated, and also to indicate the boundaries between adjacent frames of different colors of transferrable dye material. In operation the web is advanced until an index mark is detected to indicate that a transferrable color material is in position for printing.
The ribbon or web is advanced and rewound under control of the printer controller for one group or sequence of repeatable frames, to obtain the desired image on the card using the dyes on the ribbon or web. The operation is carried out a predetermined number of times so the same sequence of frames is used for printing multiple color images. After an entire sequence of frames is used for printing a color image, the web is advanced until an index mark is sensed for the next sequence of colored frames, thereby bringing the beginning of a sequence of frames in position for printing.
The present invention relates to an identification coding for a web or ribbon using laterally extended code markings between each of the color frames or segments on the ribbon that are sequenced along the ribbon length. The code is preferably in the form of readable printed dots, dashes or bars that extend laterally across the web or strip of ribbon at the start of the ribbon, between individual frames or segments, and also between repeating groups or sequences of frames. The code location and arrangement permits a wide range of identification marks to be sensed for determining the ribbon lot and dye set marks at the start of a ribbon and to indicate the color of a following frame or panel on the ribbon. These marks can be used to set the printhead controls, to adjust the printhead for ribbon density, type of color layers and similar known variables. Also, the code provides information to insure the correct ribbon or web is installed. The ribbon can also be identified by a discrete code to register the web or ribbon to a particular card printer. By using sensors to determine ribbon velocity or tension can be controlled to compensate for ribbon stretch, thus also permitting compensating or changing the ribbon tension for accommodating panel to panel variations. The code location permits determining when the leading edge of the known, repeating group, series or sequence of frames is sensed, as well.
The code selected permits a variety of printing techniques for the application of the code and also permits a wide variety of sensors for decoding. Light signals are used in one embodiment using a known source of light, and known sensor arrays that provide digital signals to the controller indicating the information about the following frames. With present sensors the presence or absence of a mark in a particular location of the sensed image provides a digital indication of the applied code and the resolution is adequate to provide more information than that needed for color printers.
In one form, the laterally extending code strips can be formed with white ink marks so a reflected light signal will be used. Sense and receive sensors can be on the same side of the ribbon. The operator can provide codes for many different conditions, since the laterally extending bands or marks provide a substantial space for such coded information. The coded information at the start of a ribbon can indicate whether the ribbon or web is compatible with the printer in which it is installed and thus different compatibilities of ribbons can be created to give different customers proprietary ribbon.
A further aspect of having markings for each individual color panel or frame is to use the color signal, which may indicate a color having different densities from other colors, to provide a feedback to the printhead power control for adjustment of the printhead power to suit the color being printed.